But whatever happens Sunday afternoon in Boston, Allen believes one thing: One day he again will be appreciated by
Celtics fans.

"Yeah, I think once the dust settles," Allen said. "When we look at what we were able to accomplish, just the winning we did."

Celtics fans might have amnesia Sunday about how the shooting guard helped their team win the 2008 NBA title and advance to the 2010 Finals and made three All-Star Games while playing in Boston from 2007-12. They might just think about Allen having bolted to the rival
Miami Heat after becoming a free agent last summer.

Sunday will mark Allen's initial return to Boston. Celtics coach Doc Rivers is hoping fans will prefer to dwell on what Allen was able to accomplish while in green.

"He made a business decision," Rivers said. "But he helped us win a championship. I hope he gets a good round of applause when he's here. He did a lot for this franchise."

"I don't expect it to be good," James said of the reception. "If you don't wear green, in that building they don't like you."

James knows quite well about a hostile return. He bolted Cleveland when he became a free agent in the summer of 2010, and was jeered in his return. James, though, said he didn't have any advice for Allen.

Heat center
Chris Bosh also knows the feeling. Any theories Canadians are always nice were quickly proved wrong when Bosh returned to Toronto for the first time after fleeing the
Raptors as a free agent in the summer of 2010.

"Boos," Bosh said of what Allen will get. "Who on this team has gotten cheers when they went back? Nobody. I don't really see it starting now."

Well, Heat forward
Shane Battier got standing ovations when he returned in November to face former teams Memphis and Houston. He even was featured in video tributes.

But Battier, while being a fine role player, isn't a future Hall of Famer. He said there's "no chance" of Allen getting a good reception.

"That's not going to happen," Battier said. "I promise you that ... It will be typical Boston. Probably not a whole lot of things fit to print."

Allen, 37, claimed he doesn't know what to expect, but he's trying to think positively.

"My [feeling] toward [the situation] doesn't change regardless of how they respond toward me," Allen said. "I have great memories. I played in some big games and won some big games, and we've had some tough moments. I'll always cherish those moments and have warm thoughts. So, regardless of how they respond to me, it won't change how I feel.

"Everybody that I've known that played on [the 2008 champions], those guys came back and they got a pretty warm welcome. Obviously, [Celtics fans will judge Allen's situation] different, I'm sure they will. But I just kind of look at the things that we did and the times that I was there that made it special."

Allen is the only member of Boston's Big Three to depart. Fellow future Hall of Famers
Paul Pierce and
Kevin Garnett remain in green.

When
Kendrick Perkins, the starting center on the 2008 and 2010 teams, returned to Boston for the first time with Oklahoma City, he was greeted warmly. But Perkins had been traded in 2011, saying he "got kicked out of there."

Still, Perkins believes Allen will hear applause Sunday.

"I would think they would give him a nice welcome and not put it in the way he made the decision," Perkins said. "He did what he felt he had to do. It was nothing personal. He just made a decision, so hopefully it all goes as we think it would."

But it doesn't help Allen's cause that he bolted to a rival. The Heat ousted the Celtics 4-3 last spring in the Eastern Conference finals.

"From a fan perspective, there's no telling," Allen, who is averaging 11.4 points coming off the bench, said of whether it made it worse that he went to Miami. "It's hard to say. But when [Allen's family] moved into this process, we weren't going to let anybody sway which direction we were going to move in. We wanted to do what was best for us all. It's almost like one of those things where you got to make a decision, you got to stand behind it and you got to be kind of selfish."

After the Heat fly to Boston on Saturday, Allen is planning to go out with some friends. No, none will be named Garnett. They will be some of Allen's golfing buddies.

Before the Heat beat the Celtics 120-107 in the Oct. 30 opener, Allen approached Rivers and gave him a hug. He then went up to Garnett, and the Celtics star ignored him.

"That's KG," Rivers said. "But they'll be friends again some day. Right now they're competitors against each other."

Rivers speaks fondly of what Allen accomplished with the Celtics. But he was disappointed Allen turned down a two-year, $12 million contract to re-sign with Boston to take a two-year, $6 million deal with the Heat.

"I wasn't happy when he left," Rivers said. "I don't think that he should have left ... But I'm bias to the Celtics. But that doesn't change that I know he's a great guy. I have a relationship with him as a person and that doesn't change. Now, I openly cheer for him to lose, but I know what kind of guy he is."

Allen was one of the most-liked players on the Celtics during his tenure, but it could take some time for that popularity in Boston to return.

"I think everybody in that city, when they can be objective and step away from it, they really appreciate Ray and everything he was able to accomplish with that group," said Miami coach Erik Spoesltra.